JP2005036865A - Constant velocity universal ball joint for vehicle steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a constant velocity universal ball joint having reduced cost by joining itself to another part as a shaft (a male shaft) without separately preparing a coupling and forming a through-hole between a coupling portion on the side of a female joint member and a space of an inner spherical joint portion to allow easy grinding of a ball guide groove. <P>SOLUTION: A male joint member 7 of the constant velocity universal ball joint 2 has a first connection base portion 71 and an outer spherical joint portion 72 with a spherical outer face. The female joint member 8 has a second connection base portion 81 and the inner spherical joint portion 82 connected to each other. In the first connection base portion 71 and the second connection base portion 81, at least one slit 711 and 811 are provided, respectively, which reach the cylindrical inside thereof. By fastening the slits to each other, the constant velocity universal ball joint 2 is joined to an input shaft and an output shaft located outside thereof. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shaft coupling device for transmitting rotation between two differently oriented shafts, and more particularly to a constant velocity ball universal joint for a vehicle steering device.
[0002]
[Prior art]
A universal shaft coupling device is used to transmit rotation or power between two axes that are not in line. A cross joint universal joint called a cardan joint, hook joint, cross joint, etc. has two shafts connected via a cross member having four cross-shaped shaft parts, and these shaft parts are opposite to each other. Two of them are supported by the yoke of each shaft.
[0003]
The constant velocity ball universal joint is formed by interposing a torque transmission ball between ball guide grooves formed on the inner surface of the inner spherical joint portion of the female joint member and the outer surface of the outer spherical joint portion of the male joint member fitted thereto. Power is transmitted between two shafts to which a male joint member and a female joint member are attached.
[0004]
The above-mentioned cross shaft universal joint has a disadvantage in that the rotation between the two axes does not become constant speed when there is an intersection angle, whereas the constant velocity ball universal joint has 2 defects even when there is an intersection angle. It has an excellent point that the rotation between the two axes is constant.
[0005]
When used in a steering apparatus, the female joint member is coupled to the input shaft or output shaft (for example, an intermediate shaft) to the female joint member by a connecting base member integrated with or integrated with the female joint member. Is usually formed integrally with an input shaft or an output shaft. However, a member coupled to the input shaft or the output shaft may be a male shaft for the convenience of other component designs. In this case, a coupling that couples the shafts is required. However, if this is done, the rotation diameter of the coupling part becomes large, and if the shaft length must be set short, a coupling can be inserted. There may not be. For this reason, such an attachment method may not be employable. Furthermore, in this case, since a separate coupling must be prepared, the cost increases due to the coupling itself and its assembly.
[0006]
Furthermore, since the torque transmission ball rolls on the ball guide groove, it is necessary to perform finish grinding (polishing) with high accuracy. However, the ball guide groove on the female joint member side is formed in the inner space so that the torque transmission ball and the outer spherical joint portion of the male joint member are accommodated inside. In addition, since this is formed at the end of the solid input / output shaft that is integral, this space necessarily has a bottom. That is, it is necessary to accurately grind the groove on the inner wall surface of the bottomed hole. Grinding the inner wall surface of the bottomed hole is not easy, and it is necessary to grind the groove inside the hole with high precision, so it takes time and cost to grind the ball guide groove on the female joint member side. is the current situation.
[0007]
[Patent Document 1]
JP 2000-257645 A [Patent Document 2]
Japanese Patent Laid-Open No. 2002-114155
[Problems to be solved by the invention]
The present invention has been made in view of the above problems, and even if the coupling partner is a shaft (male shaft), it can be coupled without preparing a separate coupling, and the female joint member side An object of the present invention is to provide a constant velocity ball universal joint for a vehicle steering apparatus in which a space between a coupling portion and an inner spherical joint portion is formed as a through hole so that the ball guide groove can be easily ground. Furthermore, this makes it a subject to provide a constant-velocity ball universal joint with low cost.
[0009]
[Means for Solving the Problems]
The above problem is solved by the following means. That is, the solving means of the first invention is a male joint provided with a cylindrical first connecting base portion and an outer spherical joint portion provided on the axis of the first connecting base portion and having a spherical outer surface. A female joint member comprising: a member, a cylindrical second connecting base portion; and an inner spherical joint portion provided on an axis of the second connecting base portion and having a spherical space into which the spherical outer surface is fitted, and the outer spherical surface An outer ball guide groove formed on the spherical outer surface of the joint portion, an inner ball guide groove formed on the inner surface of the spherical space of the inner spherical joint portion, and a torque transmitting ball guided by the outer ball guide groove and the inner ball guide groove The ball holder for holding the torque transmitting ball, and the first connection base portion and the second connection base portion each include at least one slit reaching the inside of each cylinder. A constant velocity ball joint for a vehicle steering apparatus according to symptoms.
[0010]
According to a second aspect of the present invention, there is provided a constant velocity ball universal joint according to the first aspect, wherein a pair for tightening is provided on both sides of the slit of the first connection base portion and the second connection base portion. The constant velocity ball universal joint for a vehicle steering apparatus is characterized in that a flange is formed, and a tightening hole is coaxially formed in each pair of flanges.
[0011]
According to a third aspect of the present invention, there is provided a constant velocity ball universal joint according to the first or second aspect, wherein a female serration is formed on a cylindrical inner surface of the first connection base portion and the second connection base portion. This is a constant velocity ball universal joint for a vehicle steering device.
[0012]
According to a fourth aspect of the present invention, there is provided the constant velocity ball universal joint according to any one of the first to third aspects, wherein the cylindrical hole of the second connection base portion and the spherical space of the inner spherical joint portion are provided. Is a constant velocity ball universal joint for a vehicle steering device, wherein a through hole is formed coaxially therethrough.
[0013]
According to a fifth aspect of the present invention, there is provided the constant velocity ball universal joint according to the fourth aspect of the present invention, wherein the through hole has the spherical hole between the cylindrical hole and the spherical space. A constant velocity ball universal joint for a vehicle steering apparatus, wherein a dust cap for preventing dust from entering the space is attached.
[0014]
According to a sixth aspect of the invention, there is provided a constant velocity ball universal joint according to any one of the first to fifth aspects, wherein the spherical joint is interposed between the male joint member and the female joint member. A constant velocity ball universal joint for a vehicle steering apparatus, characterized in that a cylindrical dustproof boot having a flexible hook is provided in order to prevent dust from entering.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
First Embodiment FIG. 1 is an explanatory view showing the entire steering mechanism of an automobile to which the constant velocity ball universal joint (first embodiment) of the present invention is applied. In this figure, the upper part from the vehicle body side steering mechanism 6 is shown. A steering column 52 is fixed to the vehicle body 91 by an adjustment lever 522 so that its inclination can be adjusted. The steering column 52 is rotatably supported by a wheel shaft 521 that passes through the inside of the steering column 52, and the steering wheel 51 is fixed above the wheel shaft 521. The shaft coupling device 1 is coupled to the other end, that is, the lower end side of the steering column 52.
[0016]
The shaft coupling device 1 is provided with a constant velocity ball universal joint 2 on the lower side, a constant velocity ball universal joint 2 'on the upper side, and an intermediate shaft 3 connecting these shaft couplings in the middle. The constant velocity ball universal joint 2 ′ is formed integrally with the outer spherical joint portion. Each constant velocity ball universal joint 2, 2 ′ is coupled to the wheel shaft 521, the intermediate shaft 3 and the input shaft 61 of the vehicle body side steering mechanism 6 by fastening bolts 21, 21 ′. Crossing angles α and β are crossing angles of the constant velocity ball universal joint 2, and are angles formed by the central axis of the wheel shaft 521 and the input shaft 61 with respect to the central axis of the intermediate shaft 3. The subject of the present invention is shown in this example as the lower constant velocity ball universal joint 2, which will be described below.
[0017]
2 is a front cross-sectional view of the constant velocity ball universal joint 2 of the first embodiment, FIG. 3 is a lower side view, FIG. 4A is a cross-sectional view taken along the line AA in FIG. 2, and FIG. It is B sectional drawing.
[0018]
The male joint member 7 includes a first connecting base portion 71 having a cylindrical shape and an outer spherical joint portion 72 provided on the axis of the first connecting base portion 71 and having a spherical outer surface. The female joint member 8 has a cylindrical second connecting base portion 81 and an inner spherical joint portion 82 provided on the axis of the second connecting base portion 81 and having a spherical space 823 into which the spherical outer surface fits. And are provided.
[0019]
An outer ball guide groove 721 is formed on the spherical outer surface of the outer spherical joint portion 72, and an inner ball guide groove 821 is formed on the inner surface of the spherical space 823 of the inner spherical joint portion 82. A torque transmitting ball 881 is fitted in the outer ball guide groove 721 and the inner ball guide groove 821, and is guided by these guide grooves. The rotation can be transmitted between the male joint member 7 and the female joint member 8 by the three members of the outer ball guide groove 721, the inner ball guide groove 821, and the torque transmission ball 881. Even if the axial directions are different, the rotation ratio at this time can be kept constant.
[0020]
The ball cage 882 is fitted into the spherical space 823 from the inside and from the outside to the spherical outside surface of the outer spherical joint portion 72, and holds the torque transmitting ball 881 in the hole 883 provided in the ball cage 882. Thus, the torque transmission ball 881 is prevented from being detached from each guide groove.
[0021]
The first connection base portion 71 and the second connection base portion 81 are provided with at least one slit 711 and 811 having a width of 1.5 to 6 mm, preferably 2 to 4 mm, reaching the inside of each cylinder. By tightening between the slits, the constant velocity ball universal joint 2 is coupled to a male shaft (an input shaft to the constant velocity ball universal joint 2 and an output shaft in the future), respectively.
[0022]
This fastening structure is as follows. That is, flanges 712 and 812 that form a pair for tightening are formed on both sides of the slits 711 and 811 of the first connection base portion 71 and the second connection base portion 81, respectively. The pair is formed with tightening holes, in this case, bolt holes 713 and 813 are formed on one side, and fool holes 714 and 814 are formed coaxially on the other side. The bolt hole is JIS M8 × 1.25 or M10 × 1.25. The fastening bolt 21 is passed from the side of the hole 714, 814 and screwed into the bolt hole 713, 813. Since the interval between the slits 711 and 811 is narrowed by tightening the tightening bolt 21, a coupling relationship with the male shaft (not shown) occurs. This coupling may be by frictional force, but in order to make the coupling stronger, female serrations 715 and 815 are formed on the cylindrical inner surfaces of the first coupling base portion 71 and the second coupling base portion 81. And geometrically engaged with the male serration of the male shaft. Note that, instead of serration, it is also possible to employ a combination based on geometric constraints such as a spline, an ellipse, or a polygon. Further, both of the tightening holes may be stupid holes and tightened with bolts and nuts.
[0023]
Further, the bolt holes 713 and 813 and the fool holes 714 and 814 are formed in substantially the same direction, so that the inserting direction of the bolt 21 becomes substantially the same, and the assembling work becomes easy when assembling to the vehicle. When dust enters the relative movement portions of the outer ball guide groove 721, the inner ball guide groove 821, and the torque transmission ball 881, not only wear is accelerated, but also very small torque fluctuations (feeling groovy) occur due to the biting of the dust. Therefore, the steering feeling is deteriorated. In order to prevent the intrusion of dust into the spherical space 823, a cylindrical dust-proof boot 95 made of rubber or resin is provided between the male joint member 7 and the female joint member 8 with a flexible flange. Is provided to cover this part.
[0024]
The cylindrical hole 816 of the second connection base portion 81 and the spherical space 823 of the inner spherical joint portion 82 are connected to each other, thereby forming a through-hole penetrating coaxially. The ball guide grooves 821 and 721 need to be subjected to highly accurate finish grinding (polishing) because the torque transmitting ball rolls. However, the inner ball guide groove 821 on the female joint member 8 side is formed in the inner space (spherical space 823) so that the torque transmission ball 881 and the outer spherical joint portion 72 of the male joint member 7 are accommodated inside. Yes. Conventionally, since the spherical space 823 has a bottom (that is, does not penetrate), it is very difficult to grind the inner ball guide groove 821 by simultaneously putting a grinding stone while supplying a grinding liquid from one side in a narrow space. Therefore, it takes time and cost to grind the inner ball guide groove 821 on the female joint member 8 side.
[0025]
In the constant velocity ball universal joint of the present invention, since the through-hole is formed by the cylindrical hole 816 and the spherical space 823, the above-mentioned difficulty is greatly alleviated because the grinding location can be accessed from both sides. Time and cost can be reduced. In addition, by penetrating in this way, efficient broaching can be employed for processing the female serration 815, so that the cost can be reduced. The male joint member 7 and the female joint member 8 employ cold forging, hot forging, and machining.
[0026]
Second Embodiment FIG. 5 is a front sectional view of the constant velocity ball universal joint 2 of the second embodiment, FIG. 6 (A) is a sectional view taken along the line AA in FIG. 5, and FIG. 5 (B) is a sectional view taken along the line BB. is there. The second embodiment is an example in which the male joint member 7 and the female joint member 8 are made by hot forging. Since the flange 812 on the female joint member 8 side is not constricted with the inner spherical joint portion 82, the weight is slightly increased, but the structure here is simple and the overall length can be shortened. . Since others are the same as the first embodiment, the description thereof will be used, and the duplicate description will be omitted.
[0027]
Third Embodiment FIG. 7 is a front sectional view of the constant velocity ball universal joint 2 of the third embodiment. In this embodiment, the male joint member 7 is composed of two parts for fitting the first connecting base portion 71 and the outer spherical joint portion 72, and the fitting portion is welded (welded portion 73). Since others are the same as those of the first and second embodiments, the description thereof is used, and a duplicate description is omitted. When it is necessary to increase the total length of the male joint member 7, the constant velocity ball universal joint 2 has an advantage that it can be manufactured at a relatively low cost. The first connecting base portion 71 is made by cold forging, warm forging, or hot forging and machining.
[0028]
Fourth Embodiment FIG. 8 is a front sectional view of the constant velocity ball universal joint 2 according to the fourth embodiment, and FIG. 9 is a sectional view taken along the line AA of FIG. Similar to the third embodiment, in this embodiment, the male joint member 7 is composed of two parts for fitting the first connecting base portion 71 and the outer spherical joint portion 72, and the fitting portion is welded. The first connecting base portion 71 is made of a plate material, and the portion of each flange 712 is folded. Since the spherical space 823 is continuous with the cylindrical hole 816, dust that has entered from the slit 811 may reach the spherical space 823. Therefore, a dustproof cap 96 that partitions the cylindrical hole 816 and the spherical space 823 is provided. The dust cap 96 also prevents the grease inside the spherical space 823 from flowing out. The dust cap 96 can be employed not only in this embodiment but also in other embodiments in which the cylindrical hole 816 and the spherical space 823 are continuously formed as a through hole. Others are the same as in the previous embodiments, so the description thereof will be used and redundant description will be omitted.
[0029]
Fifth Embodiment FIG. 10 is a front sectional view of the constant velocity ball universal joint 2 of the fifth embodiment. In this embodiment, a part of the dustproof boot 95 is released. In the case of the constant velocity ball universal joint 2 used in the passenger compartment, a boot having such a structure is often sufficient. Since the dustproof boot 95 makes only slight contact with the outside of the inner spherical joint portion 82 when the crossing angle is applied, it does not generate load torque (bending torque) as large as when completely sealed. There are benefits. The dustproof boot 95 can also be provided on the inner spherical joint portion 82 side. Others are the same as in the previous embodiments, so the description thereof will be used and redundant description will be omitted.
[0030]
【The invention's effect】
According to the constant velocity ball universal joint of the present invention, even if the coupling partner is a shaft (male shaft), the coupling can be performed without preparing a separate coupling. Since the space of the spherical joint portion is a through hole, the ball guide groove can be ground relatively easily. In addition, this has the effect of providing a low-cost constant velocity ball universal joint.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing the entire steering mechanism of an automobile to which a constant velocity ball universal joint of the present invention (first embodiment) is applied.
FIG. 2 is a front sectional view of the constant velocity ball universal joint 2 according to the first embodiment.
FIG. 3 is a lower side view of the constant velocity ball universal joint 2 of the first embodiment.
4A is a cross-sectional view taken along line AA in FIG. 2, and FIG. 4B is a cross-sectional view taken along line BB in FIG.
FIG. 5 is a front sectional view of the constant velocity ball universal joint 2 of the second embodiment.
6A is a cross-sectional view taken along the line AA in FIG. 5, and FIG.
FIG. 7 is a front sectional view of a constant velocity ball universal joint 2 of a third embodiment.
FIG. 8 is a front sectional view of a constant velocity ball universal joint 2 according to a fourth embodiment.
9 is a cross-sectional view taken along the line AA in FIG.
FIG. 10 is a front sectional view of a constant velocity ball universal joint 2 of a fifth embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Shaft coupling apparatus 2, 2 'Constant-velocity ball universal joint 21, 21' Tightening bolt 3 Intermediate shaft 52 Steering column 521 Wheel shaft 522 Adjustment lever 6 Car body side steering mechanism 61 Input shaft 7 Male joint member 71 1st connection base part 711 Slit 712 Flange 713 Bolt hole 714 Float hole 715 Female serration 72 Outer spherical joint portion 721 Outer ball guide groove 73 Welded portion 8 Female joint member 81 Second connecting base portion 811 Slit 812 Flange 813 Bolt hole 814 Flaw hole 815 Female serration 816 Cylindrical Hole 82 Inner spherical joint portion 821 Inner ball guide groove 823 Spherical space 881 Torque transmission ball 882 Ball cage 883 Hole 91 Body body 95 Dustproof boot 96 Dustproof cap

Claims (6)

A male joint member comprising a cylindrical first connecting base portion and an outer spherical joint portion having a spherical outer surface provided on the axis of the first connecting base portion;
A female coupling member comprising a cylindrical second coupling base portion and an inner spherical coupling portion provided on the axis of the second coupling base portion and having a spherical space into which the spherical outer surface is fitted;
An outer ball guide groove formed on the spherical outer surface of the outer spherical joint portion;
An inner ball guide groove formed on the inner surface of the spherical space of the inner spherical joint portion;
A torque transmitting ball guided by the outer ball guide groove and the inner ball guide groove;
A ball holder for holding the torque transmitting ball; and
The constant velocity ball universal joint for a vehicle steering apparatus, wherein the first connection base portion and the second connection base portion include at least one slit reaching the inside of each cylinder. The constant velocity ball universal joint according to claim 1,
On both sides of the slit of the first connection base portion and the second connection base portion, a pair of flanges for fastening are formed, respectively.
A constant velocity ball universal joint for a vehicle steering system, wherein a tightening hole is formed coaxially in each pair of flanges. In the constant velocity ball universal joint for a vehicle steering device according to claim 1 or 2,
A constant velocity ball universal joint for a vehicle steering apparatus, wherein female serrations are formed on cylindrical inner surfaces of the first connection base portion and the second connection base portion. In the constant velocity ball universal joint for vehicle steering devices according to any one of claims 1 to 3,
A constant velocity ball universal joint for a vehicle steering system, wherein a through-hole penetrating coaxially is formed between the cylindrical hole of the second connecting base portion and the spherical space of the inner spherical joint portion. . In the constant velocity ball universal joint for the vehicle steering device according to claim 4,
The through hole is provided with a dust-proof cap between the cylindrical hole and the spherical space for preventing dust from entering the spherical space through the cylindrical hole. A constant velocity ball universal joint for a vehicle steering device. In the constant velocity ball universal joint for a vehicle steering device according to any one of claims 1 to 5,
A cylindrical dustproof boot having a flexible hook is provided between the male joint member and the female joint member to prevent dust from entering the spherical space. Constant velocity ball universal joint for vehicle steering system.

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